Circuit breaker blast valve mechanism



Dec. 20, 1955 E. FRISCH CIRCUIT BREAKER BLAST VALVE MECHANISM 3 sheets-sheet 1 Filed June 26, 1953 Fig.|.

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Insulation INVENTOR Erling Frisch. BY a] AT WITNESSES: Z4

TORNEY Dec. 20, 1955 E. FRISCH CIRCUIT BREAKER BLAST VALVE MECHANISM 3Sheets-Sheet 2 Filed June 26, 1953 R h Y m c E m B M r W I W F m 5 I. gM :1 h n FIIIIIIIIII H 3 r I 7 I M& 2 2 fi544fl 3 7 9 X 222 M. w 9 Z 7MI 9 I w m a w 8 2 i\ a 0 IB 3 m 9 4 $8 .8 I I 2 4 2 w. H

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Dec. 20, 1955 E. FRISCH 2,

CIRCUIT BREAKER BLAST VALVE MECHANISM Filed June 26, 1953 S Sheets-Sheet3 Erling Frisch.

United States Patent 2,727,714 CIRCUIT BREAKER BLAfiT VALVE MECHANISMErling Frisch, Pittsburgh, Pa., assignor to Westinghouse ElectricCorporation, East Pittsburgh, Pa., a corporation of PennsylvaniaApplication June 26, 1953, Serial No. 364,459

8 Claims. (Cl. 251-25) operation by fluid pressure, such as compressedair, and

have been provided with means forseparating the contacts andextinguishing the are drawn upon separation of the contacts comprising ablast valve. mechanism operation atthe proper instant to subject thecontacts to a sudden blast of fluid under pressure.

A blast valve mechanism designed for such service must be adapted forhigh-speed operation since it is desirable to insure operation of thecircuit breakers within a very small time interval. The blast valvemechanism must alsobe capable of high-speed closing in order to preventexcessive loss of fluid pressure, and should be operative to control thesupply of fluid under a high pressure, which may be in the neighborhoodof 350 pounds per square inch.

An object of the invention is to provide an improved blast valvemechanism capable of high-speed opening and closing operations. t

Another object of the invention is to provide an improved high-speed,fluid-pressure-operated blast valve em bodying a fluid-pressure-operatedpilot valve for control ling the operation of the blast valve.

Another object of the invention is to provide an improved blast valvemechanism for a circuit interrupter comprising a main valve element,fluid pressure means for actuating the main valve element, a pilot valveand a secondary valve cooperating to effect a sudden variation in thepressure of fluid on the fluid pressure means to effect high-speedoperation of said main valve element.

Still another object of the invention is to provide an improvedhigh-speed blast valve mechanism according to the proceeding paragraphsembodying valve means operable to prevent loss of fluid pressure duringopening'and closing movement of the pilot valve and when the pilot valveis open.

The invention both as to structure and operation, together withadditional objects and advantages thereof, will be best understood fromthe following detailed description of a preferred embodiment thereof,when read in conjunction with the accompanying drawings.

in said drawings:

Fig. l is a side elevational view of a circuit interrupter embodying theprinciples of the invention.

Fig. 2 is an enlarged sectional view of a portion of the circuitinterrupter showing the arc extinguishing structure of the circuitinterrupter and the blast valve mechamsm.

Fig. 3 is an enlarged sectional view of the blast valve mechanismshowing the blast valve in the closed position. Fig. 4 is a view similarto Fig. 3, but showing the blast valve in the open position.

The invention is illustrated as applied to a circuit in- 2 r terrupterof the general type disclosed in copending appli-. cation Serial No.180,447, filed by Benjamin F. Baker, August 19, 1950, now Patent No.2,644,876, issued July 7, 1953, and assigned to the assignee of theinstant invention.

Referring to Fig. l of the drawings, the circuit inter: rupter issuitably supported on a base comprising a framework indicated generallyat 11. Mounted on the framework 11 are tubular insulators 13 and 15 anda metal housing indicated generally at 17 is mounted on the upper end ofthe tubular insulator 15. A tubular insulator 19 mounted on the housing17 supports a metal housing 21 which encloses the moving contactstructure of an interrupter. Mounted on the metal housing 21 is atubular insulator 23 which at its upper end supports a metal housing 25enclosing an upper exhaust chamber and a metal cap 27 is mounted on thehousing 25.

Suitably supported in the framework 11 is a compressed-airtanli orreservoir 29 having an elbow 31 secured to one end thereof upon whichelbow is supported an insulating tube 33 which extends upwardly withinthe tubular insulators 13 and 15 and terminates below the housing 17. Asshown in Fig. 2, the housing 17 is divided into two compartments, thelower compartment 35 comprising a highpressure compartment and the upperone 37 comprising an exhaust compartment. A Y-shaped tube 39 (only oneleg of which is shown) is connected to a cap 40 mounted on the upper endof the tube 33 and communicates with the high-pressure compartment 35.One of the legs of the tube 39 is disposed back of the blast valvemechanism, indicated generally at 41, and the other (not shown)communicates with the high pressure chamber in front of the blast valvemechanism.

The housing 17 for the high pressure chamber 35, the exhaust chamber 37and for enclosing the mechanism in the space just below the highpressure chamber comprises a base casting 43 (Figs. 1 and 2),; mountedon top of the tubular insulator 15. A plate 45 is suitably securedpreferably by welding, on the casting 43 and plates 47 and 49 aresecured to the plate 45 to form a box-like enclosure having covermembers 51 (Figs. 1 and 2) removably mounted thereon for covering accessopenings. Mounted on the plates 47-'49 is a plate 53 forming the bottomof the high-pressure chamber and a similar plate 55 forms the top of thehigh-pressure chamber. Side walls 57 mounted between the bottom disc 53and the top disc 55 complete the high-pressure chamber. I,

The exhaust chamber 37 is formed by the plate 55 and a casting 59 havingside members 61 mounted therebetween, the parts being secured preferablyby welding. Integral with the casting 59 is a tubular extension 63 whichextends downwardly into the exhaust chamber and disposed centrallywithin the tubular extension is a tubular divider 65 closed at itslower'end and supported by means of a spider 67 integral with thecasting 59 and with the divider 65. Openings 69 through thespidercommunicates the interior of the divider 65 with the exhaustchamber 37. M

A tubular stationary contact member 71 threadedly engaging the upper endof the divider 65 has a stationary contact 73 mounted on the upper endthereof for cooperation with a lower movable contact member 75 disposedin the contact housing 21. An upper movable contact 77 also disposed inthe contact housing 21 cooper,- ates with an upper stationary contact 79which is sup.- ported on an upper stationary contact member .(not shown)like the contact member 71. The-upper statioi1 ary contact member ishoused in th'e'tubular insulator 23 and terminates in the exhaustchamber 25. The arrangement of the upper stationary contact and theexhaust chamber 25 is the same as that for the cover contact except thatit is inverted. Y I

The movable contacts 75 and 77 are connected bye flexible conductor 81and are pivotally supported respectively onthe inner .ends of links .83and 85 by .means of pivot pins 87 and 89. The outer ends of the links 83and 85 are pivoted respectively on pivot pins 91 and 93 supported on aremovable cover plate 95. The inner ends of the links 83 and85 areconnected by a toggle comprising toggle links 97 and 99 which arepivoted on the pins 87 and 89 and pivotally connected together by a kneepivot pin 101. A spring seat 103 is mounted on the knee pivot pin 101and a coil spring 105 compressed between the spring seat 103 and theplate 95 biases the knee of the toggle 9799 in a direction to extend thetoggle, thereby applying contact pressure between the movable con-'tacts 75 and 77 and the corresponding stationary contacts 73 and 79. Aspring guide 107 is provided on the plate 95 for guiding the spring 105.

The circuit through the interrupter extends from a line terminal 109(Fig. 1) through the upper exhaust housing 25 and the upper stationarycontact means (Fig. 2) including the upper stationary contact 79, theupper movable contact 77, the flexible conductor 81, the lower movableand stationary contacts 75, 73, lower contact member 71, the housing 17(Fig. 1), a shunt conductor 111, a disconnect switch comprising asupport member 113 secured to the casting 43 by means of bolts (notshown), a disconnect switch blade 115, a stationary disconnect contact117 and a line terminal 119.

The support member 113 which is rigidly mounted on the casting 43 isalso supported on a rotatable column comprising an insulator 121 and amember 123. The stationary'disconnect contact 117 and the line terminal119 are mounted on an insulator 125 supported on the general framework11. Since the'disconnect switch forms no part of the present invention,a detailed description thereof will not be given. It is believedsuflicient to set forth that the switch is operated to the open positionby means of a compressed gas operating mechanism indicated generally at127 which, when actuated, swings the column 121123 to effect openingmovement of the disconnect switch blade 115. 1

The blast valve mechanism for admitting a blast of compressed gas toblast the movable contacts open and extinguish the arc is mounted in acasing or cylinder 129 (Figs. 2, 3 and 4) disposed in central openingsin the plates 53 and 55 and rigidly secured thereto preferably bywelding. The upper end of the casing 129 abuts against the lower end ofthe extension 63 with a sealing gasket therebetween to form a continuouspassage. As best seen in Figs. 3 and 4 a cylindrical valve member 131 isremovably mounted in a bore in the lower end of the cylinder 129 withthe upper end thereof abutting a shoulder 133 in the bore of thecylinder 129. A member 135 disposed in the lower end of the bore of thecylinder 129 has a flange 137 thereon closely fitting in the bore of thecylinder 129 at the lower end of the valve member 131. The member 135and the valve member 131 are held in place by an annular member 139having a cylindrical extension 141 cooperating with the flange 137 ofthe member with a sealing gasket therebetween. The annular member 139 isprovided with a flange 143 and is secured to the enlarged lower end ofthe cylinder 129 by means'of a series of bolts 145 passing throughopenings in the flange 143 and threaded into tapped openings in the endof the cylinder 129.

A valve seat 147 integral with the upper end of the cylindrical valvemember 131 cooperates with a blast valve 149 on the upper end of a valvepiston or abutment'lSl slidably mounted in the bore of the valve element131. The valvepiston or abutment 151 is in the shape of an invertedcupand together with the valve element '131'forms a chamber 152 below theabutment 151. A central tubular extension 153 extends downward'from theupper portion of the valve piston and has a"bore"154 therein. Slidableinthe bore 154 of the tubular extension 153 is a secondary valve 155closed at its upper end and having radial passages 156 therein adjacentthe upper end thereof. A flange 157 supported by a spider integral withthe lower end of the secondary valve is normally biased by means of acompression spring 159, disposed between the abutment 151 and the flange157 of the secondary valve, into engagement with an inner flange 161 onthe member 135. The spring 159 also biases the blast valve 149 closed.

A pilot valve 163 normally engaging a valve seat 165 is mounted on theupper end of a valve stem 167 slidably mounted in a valve guide 169. Thevalve guide 169 forms the center portion of a spider 171 which issecured to the valve seat 165 by screw bolts 173 (only one being shown)and both the spider 171 and the valve seat are secured in a counterborein the bottom of the member 135 by means of screw bolts 175 (only onebeing shown). A coil spring 177 compressed between the lower side of thespider 171 and a washer 179 seated against a nut 181 threaded onto thelower portion of the valve stem 167 biases the pilot valve 163 intoengagement with the valve seat 165, thus closing oil? the centralpassage through the valve seat.

By removing the bolts 145 and disconnecting a link 185, the entire blastvalve device including the cylindrical valve member 131 may be removedfrom the cylinder 129 for inspection or repairs.

Disposed for sliding movement within the bore of the secondary valve 155is a piston valve 134 having an integral portion 186 biased against theupper face of the pilot valve 163 by means of a spring 188 compressedbetween the closed end of the secondary valve 155 and the portion 186 ofthe piston valve 184.

It will be noted that in the closed positions of the pilot valve 163 andthe blast valve 149, the secondary valve 155 closes oif the chamber 152below the abutment 151 from the high-pressure chamber 35 and that theupper end of the piston valve 184 is just below the radial passages 156in the secondary valve.

In order to operate the pilot valve 163 to eiiect opening of the blastvalve 149, a member 183 threaded onto the lower end of the valve stem167 has its lower end bifurcated to receive the upper end of the linkwhich is pivotally connected to the member 183 by means of a pivot pin187. The lower end of the link 185 is pivotally connected by means of apivot pin 189 to one end of a lever 191 pivotally supported between itsends by a pivot pin 193 mounted in a bracket 195 (Fig. 2) secured to thecap 40 preferably by welding. Pivotally connected to the other end ofthe lever 191 by means of a pivot pin 197 is the upper end of aninsulating operating rod 199 having a piston 201 (Fig. 1) connected tothe lower end thereof. The piston 201 is disposed in a cylinder 203supported on the framework 11 by means of brackets 205.

Compressed gas is admitted to the cylinder 203 above the piston 201 tooperate the rod 199 and the pilot valve 163 by means of a valvemechanism indicated generally at 207, operated by an electromagnet 209.The valve mechanism is connected to the reservoir 29 by means of a pipe211. The valve mechanism is of a wellknown type which in the closedposition shuts off a passage for admitting compressed gas to theoperating cylinder on the working side of the piston and opens a passagewhich vents the cylinder on the working side of the piston toatmosphere. When operated by the electromagnet, the valve closes oif thevent to atmosphere and opens the passage to admit compressed gas to thecylinder on the working side of the piston to operate the piston.

The blast valve is of the balanced pressure type and is operated to openposition by the high-pressure gas on top of the abutment uponunbalancing the pressure below the abutment. This is effected by openingthe pilot valve 163 and dumping the pressure from the space below theabutment 151.

When the electromagnet 209 (Fig. 1) is energized it operates the valvedevice 207 to admit compressed gas to the cylinder 203 above the piston201 moving the piston and the operating rod 199 downward. This movementrocks the lever191 (Figs. 2 and 3) clockwise unsealing the pilot valve163 and dumping the gas pressure from the space below the abutment 151to atmosphere. The opening movement of the pilot valve moves the pistonvalve 184 upward to the position shown in Fig. 4 shutting 011 thepassages 156 in the secondary valve 154. As soon as this pressure in thechamber 152 below the abutment 151 is dumpedto atmosphere thehigh-pressure gas above the abutment 151 blasts the abutment downward toopen the blast valve port and admitting a blast of high pressure gasupwardly through this cylinder 129, through the passages around thedivider 65 (Fig. 2) and through the space between the stationary contactmember 71 and the inner wall of the tubular insulator 19 to the spacearound the lower stationary contact 73 and lower movable contact 75. Theblast of high-pressure gas flows through passages 217 (Fig. 2) past thecontact housing 21 to the space around the upper movable and stationarycontacts 77-79. The high-pressure gas blasts the movable contacts 75-77inwardly to the open positionagainst a stop member 223 mounted on andextending inwardly from cover member 225 secured to the housing 21. Thehighpressure gas then flows through openings 219 and 221 respectively inthe lower and upper stationary contacts 77 and 79 extinguishing the arcand then passing downwardly through the interior of the tubularstationary contact 71 and through the openings 69 into the exhaustchamber 37. The upper stationary contact 79 is mounted on a tubularcontact member (not shown) like the contact member 71 except that it isinverted and the compressed gas fiows upwardlythrough the tubularcontact member into an upper exhaust chamber indicated at 25 (Fig. 1).The shock of the high-speed opening movement of the blast valve. piston151 is absorbed by a plurality of spring washers 226.

The compressed gas is not immediately dumped from the exhaust chamber37. A dump-valve indicated generally at 227 (Fig. 2) is provided tocontrol the dumping of the compressed gas'from the exhaust chamber, butthis dump valve is prevented from functioning until the blast valvecloses. The dump valve 227 comprises a valve housing 229 having athreaded portion 231 threaded into a tapped opening 233 in the member61. A piston valve 235 disposed in the bore of the housing 229 is biasedclosed by a spring 237 to normally close otf an exhaust port 239 in thehousing 229. The construction of the valve member 235 is such thatcompressed gas in the exhaust chamber 37 will blast the exhaust valveopen, however, means is provided operative upon opening of the pilotvalve 163 to supply high-pressure gas from the high-pressure chamber 35to the space above the piston valve 235 to prevent opening movement ofthe valve until the pilot valve 163 closes to effect closure of theblast valve.

The pilot valve 163 is closed by the spring 177 (Figs. 2, 3 and 4) upondeenergization of the electromagnet 299 (Fig. 1). When the magnet 209 isdeenergized, the valve device 267 closes oif the compressed gas from thecylinder 203 whereupon the spring 177 closes the valve 163 and rocks thelever 191 (Fig. 2) counterclockwise raising the operating rod 199. Whenthe pilot valve 163 closes, the spring 188 causes the piston valve 184to move downward therewith opening the passages 156 through thesecondary valve 155 permitting the pressure above and below the piston151 to quickly come into balance through openings 213 in the cylinder129, the radial passages 215 in the abutment 151 and the radial passages156 in the secondary valve 155. As soon as the pressure above and belowthe abutment 151 is balanced, the spring 159 snaps the abutment 151upwardly to quickly close the blast valve.

Conventional valves of the balanced-pressure type are usually providedwith a very small bypass passage for balancing the gas pressure on bothsides of the valve. Such 6 a restricted bypass passage retards the flowof highpressure gas and balancing of the pressures thereby delayingclosing of the valve. In order to effect high-speed closing of the blastvalve a relatively large bypass passage is required to quickly balancethe pressures on both sides of the abutment. However, a relatively largebypass pas sage permits a substantial loss of high-pressure gas when thepilot valve is open or during the opening and closing movements of thepilot valve. An important feature of the invention is the provision ofmeans for closing off the bypass passage except for the period of timeafter the pilot valve 163 closes and before the abutment 151 is moved tothe closed position.

The means for controlling the bypass passage 215156 comprises theextension 153 on the movable abutment 151, the secondary valve 155 andthe piston valve 184. It was previously-described how in the closedposition of the blast valve mechanism 41 (Fig. 3) the extension 153 onthe movable abutment 151 cooperates with the secondary valve 155 toclose 011 the high-pressure chamber 35 (Fig. 2) from the chamber 152below the abutment, and also how the opening movement of the pilot valve163 moves the piston valve 184 to close 011 the passages 156 in thesecondary valve 155 during the opening movement of the abutment 151 andwhile both the abutment and the pilot valve 163 are in the open positionas shown in Fig. 4. This prevents any loss of high-pressure gas from thehigh pressure chamber during opening of the pilot valve and the blastvalve and while both of these members are in the open position.

Upon deenergization of the electromagnet 209 (Fig. l) the pilot valve163 is closed by the valve spring 177. As the pilot valve moves to theclosed position, the spring 188 forces the piston valve 134 downwardlyto open the passages 156 and allows compressed gas to flow from thehigh-pressure chamber 35 to the space below the abutment 151. Thisoccurs when the pilot valve 163 is at or near its closed position sothat there is little if any loss of highpressure gas. As soon as thepressure below the abutment 151 is substantially balanced with thepressure above the abutment the spring 159 moves the blast valve to thethe abutment which compensates for any leakage of-fluid pressure pastthe pilot valve 163. An annular groove 216 (Figs. 3 and 4) is providedin the blast valve just below the valve position to provide a slightflexibility to the outer portion of the valve element which engages thevalve seat thereby effecting an air-tight seal.

It was previously mentioned that the compressed gas is not immediatelydumped from the exhaust chamber 37 (Fig. 2) and that the dumping ofcompressed gas is controlled by the dump valve 227 which is, in turn,controlled by compressed gas supplied thereto from the high-pressurechamber 35.

The means for supplying gas pressure above the piston valve 235 (Fig. 2)comprises a valve device indicated gen-. erally at 241 (Fig. 2). Thevalve device includes a housing 243 having a bore 245 therein in whichis disposed a piston valve 247 which is operated to open and closepositions by the movement of the operating rod 199 through the agencyor" a piston rod 249. When the mechanism is in the normal position withthe pilot valve 163 closed, the

piston valve 247 is in the upper position as shown in which position thevalve 247 closes a passage 251 in the housing 243. One end of thepassage 251 is connected by means of a pipe 253 to the highpressurechamber 35 and the other end of the passage 251 is connected to thespace in the housing 229 above the dump valve piston 235 by a pipe 255.Thus the piston valve 247 normally closes off the passage 251 and at thesame time opens an exhaust passa .257 wh ch mm n ca s t e pipe 2 anhence h pace abo e he dump valve 23.5 atm sphere- When ,theelectromagnet 209 (Fig. l) is energized to etfect downward movement ofthe operating rod 199 and Qpenins o th Pi o a ve 63 o initiate. ope i ofe blast valve, the piston valve 247 (Fig. 2) is moved downar o c ose theexhau pa sage 2 nd p the p sage 251, Compressed gas is thereby admittedto the dump valve 227 to hold the valve closed until the mechanism ,isoperated to effect closure of the blast valve.

When the clectromagnet 209 (Fig. 1) is deenergized to permit closure ofthepilot valve 163 (Fig. 2) the rod 199 is moved upwardly moving thevalve 247 upwardly to its normal position. This shuts off the flow ofpressure to the dump valve 227 and vents the pressure from above thevalve member 235 to atmosphere through the exhaust passage 25?. Thehigh=pressure gas in the exhaust chamber .37 then blasts the valve 235open and dumpsthc pressure from the exhaust chamber 37, the space aroundthe movable contacts and above the blast valve .to atmosphere. When thepressure adjacent the movable contacts 75.77 falls below a predeterminedlcvelthe spring 105 acts to move the contacts 7 5.77 to the closedposition. Also, when the pressure in the exhaust chamber 37 falls to apredetermined level the spring 237 closes the dump valve 235.

A dump valve 227 (Fig. 1) is provided for dumping the compressed gasfrom the upper exhaust chamber The upper dump valve 227 is exactly likethe lower aludurnp valve and is controlled by high-pressure gas ad- 0mitted thereto by the valve device 241 (Fig. 2) through the pipe 255 andan insulating pipe 259 (Figs. 1 and 2).

The invention provides a high-speed air blast valve mechanism for acircuit interrupter that is removable asa unit for inspection and/orrepairs. The blast valve is grooved or undercut just below the valveportion to provide a slight flexibility to the outer portion of thevalve element which engages the valve seat making an airtight seal. Thevalve mechanism uses a common spring for biasing the blast valve closedand for providing seating pressure between the pilot valve and themovable secondary valve. The piston valve and the secondary valvecooperate with the pilot valve and the movable abutment to providehigh-speed closing of the blast valve and also prevents loss ofcompressed gas during opening and closing movements of the pilot valveand the movable abutment and when both of these valves are in the openposition.

Having described the invention in accordance with the requirements ofthe patent statutes, it is to be understood that various changes andmodifications may be made in the structure details thereof withoutdeparting from some of the essential features of the invention.

I claim as my invention:

1. In a circuit interrupter having separable contact means and means fordirecting a blast of fluid under pressure toward said contact means forseparating said contact means and for extinguishing the arc drawn duringseparation of said contact means, a blast valve device having an inletpassage and a discharge passage, blast valve means for controlling theflow of fluid under pressure from said inlet passage to said outletpassage, a movable abutment operative by the fluid pressure from saidinlet passage for actuating said blast valve means, a secondary valveelement having passage means therein communicating said inlet passagewith the space on the opposite side of said movable abutment forbalancing the fluid pressure on both sides of said abutment, a tubularextension on said movable abutment slidably engaging said secondaryvalve element to normally close said passage means, a normally closedpilot valve controlling an exhaust port from said space on said oppositeside of said abutment, means for operating said pilot valve to openposition .to suddenly unbalance the fluid pressure onone side of saidmovable abutment to effect opening movemen at sai as val e me ns, a d aal ber movable by said pilot valve when said pilot valve is moved toopen position to close said passage means he sa p o v lv is in aid openposition- 2. In a circuit interrupter having separable contact means andmeans for directing a blast of fluid under pressure toward said contactmeans for separating said contact means and for extinguishing the aredrawn during separation of said contact means, a blast valve devicehaving an inlet passage and a discharge passage, blast valve means forcontrolling the flow of fluid under pressure from said inlet passage tosaid outlet passage, a movable abutment operative by the fluid pressurefrom said inlet passage for actuating said blast valve means, asecondary valve element having passage means therein communicating saidinlet passage with the space on the opposite side of said movableabutment for balancing the fluid pressure on both sides of saidabutment, a tubutar extension on said movable abutment slidably engagings ec d y al elemen to no ma ly clo i Passage mea a orma y osed Pil t vale controlling an exhaust p t from said pace oi -sa d oppo s f saidabutment, means for operating said pilot valve to open position tosuddenly unbalance the fluid pressure on one side of said movableabutment to effect opening movement of said ,blast valve means, saidabutment when moved toopen said blast valve means causing said tubularextension to open said passage means, and .a-valve member movable bysaid pilot Valve when said pilot valve is moved to open position toclose said passage means when said pilot valve is in said open position.

3. In a circuit interrupter having separable contact means and means fordirecting a blast of fluid under pressure toward said contact means forseparating said contact means and for extinguishing the arc drawn duringseparation of said contact means, a blast valve device having an inletpassage and a discharge passage, blast valve means for controlling theflow of fluid under pressure from said inlet passage to said outletpassage, a movable abutment operative by, the fluid pressure from saidinlet passage for actuating said blast valve means, a secondary valveelement having passage means therein communicating said inletpassagewith the space on the opposite side of said movable abutment forbalancing the fluid pressure on both sides of said abutment, a tubularextension on said movable abutment slidably engaging said secondaryvalve element to normally close said passage means, a normally closedpilot valve controlling an exhaust port from said space on said oppositeside of said abutment, means for operating said pilot valve to openposition to suddenly unbalance the fluid pressure on one side of saidmovable abutment to effect opening movement of said blast valve means,said abutment when moved to open said blast valve causing said tubularextension to open said passage means, and a valve member movable by saidpilot valve when said pilot valve is moved to open position to closesaid passage means when said pilot valve is in said open position, andsaid pilot valve when moved to closed position permitting said valvemember to open said passage means to quickly balance the fluid pressureon both sides of said abutment to thereby effect high-speed closure ofsaid blast valve means.

4. in a circuit interrupter having separable contact means and means fordirecting a blast of fluid under pressure toward said contact means forseparating said contact means and for extinguishing the are drawn duringseparation of said contact means, a blast valve device having an inletpassage and a discharge passage, blast valve means for controlling theflow of fluid under pressure from said inlet passage to said dischargepassage, a movable abutment operative by the fluid pressure from saidinlet passage for actuating said blast valve means, passage meanscommunicating said inlet passage with the space on the opposite side ofsaid abutment, a normally closed pilot valve operable to open positionto suddenly unbalance the fluid pressure on one side of said abutment toeffect opening of said blast valve means, and normally closed valvemeans for opening said passage means only when said pilot valve isclosed and said blast valve means is open for quickly balancing thefluid pressure on both sides of said abutment to eflect highspeedclosing of said blast valve means.

5. In a circuit interrupter having separable contact means and means fordirecting a blast of fluid under pressure toward said contact means forseparating said contact means and for extinguishing the are drawn duringseparation of said contact means, a blast valve device having an inletpassage and a discharge passage, blast valve means for controlling theflow of fluid under pressure from said inlet passage to said dischargepassage, a movable abutment operative by the fluid pressure from saidinlet passage for actuating said blast valve means, spring means biasingsaid blast valve means closed, means defining passage meanscommunicating said inlet passage with the space on the opposite side ofsaid abutment, a normally closed pilot valve operable to open positionto suddenly unbalance the fluid pressure on one side of said abutment toefiect opening of said blast valve means, and normally closed valvemeans actuated conjointly by said movable abutment and said pilot valvefor opening said passage means only when said pilot valve is closed andsaid blast valve means is open for quickly balancing the fluid pressureon both sides of said abutment to permit said spring means to effecthigh-speed closing of said blast valve means.

6. In a circuit interrupter having separable contact means and means fordirecting a blast of fluid under pressure toward said contact means forseparating said contact means and for extinguishing the are drawn duringseparation of said contact means, a blast valve device having an inletpassage and a discharge passage, blast valve means for controlling theflow of fluid under pressure from said inlet passage to said dischargepassage, a movable abutment operative by fluid pressure from said inletpassage for actuating said blast valve to the open position, meansbiasing said blast valve closed, passage means communicating said inletpassage with the space on the other side of said abutment to balance thefluid pressure on both sides of said abutment, a normally closed pilotvalve operable to open position to suddenly unbalance the fluid pressureon one side of said abutment to eflect high-speed opening of said blastvalve means, a secondary valve coacting with a portion of said abutmentto close said passage means when said blast valve means is closed, avalve member actuated by said pilot valve and coacting with saidsecondary valve, said secondary valve, said portion of said abutment andsaid valve member cooperating to open said passage only when said blastvalve means is open and said pilot valve is closed to quickly balancethe fluid pressure on both sides of said abutment to permit said springmeans to effect high-speed closure of said blast valve means.

7. In a blast valve mechanism for a circuit interrupter, the combinationof a casing structure having an inlet passage supplied with fluidpressure, a discharge passage and a pressure chamber in said casingstructure, a main valve disposed in said casing structure forcontrolling the flow of fluid under pressure from said inlet passage tosaid discharge passage, a movable abutment disposed between said inletpassage and said chamber for operating said main valve, means defining arelatively large passage for admitting fluid under pressure from saidinlet passage to said chamber, a pilot valve disposed in said casing andautomatically operative to vent fluid pressure from said chamber toinitiate operation of said main valve by said movable abutment, andnormally closed valve means actuated conjointly by said movable abutmentand said pilot valve to open said passage only when said movableabutment is in operated position and said pilot valve is in closedposition.

8. in a blast valve mechanism for a circuit interrupter, the combinationof a casing structure having an inlet passage adapted to be suppliedwith fluid under pressure, a discharge passage and a chamber in saidcasing structure, a main valve disposed in said casing structure forcontrolling the flow of fluid under pressure from said inlet passage tosaid discharge passage, a movable abutment disposed between said inletpassage and said chamber for operating said main valve, means defining acommunication for admitting fluid under pressure from said inlet passageto said chamber, a pilot valve automatically operative to vent fluidpressure from said chamber to effect high-speed opening operation ofsaid main valve by said movable abutment, normally closed valve meansfor controlling said communication comprising a centrally disposed valvemember, a first valve operated by said movable abutment, a second valveoperated by said pilot valve, said first and second valves cooperatingwith said controlling valve means and operative only when said mainvalve is open and said pilot valve is closed to open said communicationto admit fluid pressure from said inlet passage to said chamber toinitiate a high-speed closing operation of said main valve.

Henderson Jan. 30, 1900 Baker Oct. 10, 1950

